1. Field of the Invention
Our invention is a mount specifically designed for use with an X-ray diffractometer.
2. Description of the Prior Art
Over the years various types of mounts have been used to mount specimens which are then subjected to some type of analysis. In one case the specimen is inserted in indents and held in place by a pair of brackets so that it may thereafter be exposed to a source of X-rays (U.S. Pat. No. 3,340,397 to R. L. Johnston). When X-ray diffraction is used as the technique to analyze the sample, a vacuum chuck can be used to hold the sample (U.S. Pat. No. 4,078,175 to J. C. Fletcher et al.) or it may be held or mounted in a rotatable holder (U.S. Pat. No. 3,852,594 to F. R. Paolini). Another mounting procedure useful with X-ray fluorescence, (U.S. Pat. No. 3,536,912 to W. Speck et al) provides for a suspended mount with adjusting screws to avoid static uncertainties.
U.S. Pat. No. 4,115,689 to V. Y. Won appears, at first glance, structurally close to this patent invention. However, the Won patent is designed specifically for X-ray fluorescence whereas our invention is concerned with X-ray diffraction. These two different uses bear on and specifically relate to the structural differences between the two inventions which make interchangeability virtually impossible. Although both X-ray fluorescence and X-ray diffraction employ the principles of Bragg's Law (n.lambda.=2.theta. sin .theta.), in X-ray fluorescence the wavelength .lambda. is in the unknown and in X-ray diffraction the interplanar spacings (d) of the minerals are the unknowns. Our invention employs an especially selected filter which underlies the sample and in no way interfers with the diffracted incident X-ray beam whereas in the Won reference a plastic film is placed over the sample to keep the sample surface flat. If such a plastic film were used with X-ray diffraction the plastic itself would superimpose its own diffraction effects over those of the sample. With X-ray fluorescence, the method Won is specifically designed for, the plastic filter would have no effect. Other structural differences limiting our mounting to automatic sample changes useful for X-ray diffraction and Won's to X-ray fluorescence will become apparent as the remainder of this disclosure is read.
In the article authored by us entitled "A Metal-Membrane Mount for X-ray Powder Diffraction" first published on Apr. 1, 1979, in Volume 27, No. 2, pages 152-153 of the periodical "Clays and Clay Minerals" many of the details relating to this invention are disclosed including its mounting procedure. The contents of that article are specifically incorporated by reference herein.